Oscillating mechanisms



Dec. 19, 1961 Filed Nov. 14, 1958 D. A. GODDARD OSCILLATING MECHANISMS 5Sheets-Sheet 1 ODDfl/PD Dec. 1961 D. A. GODDARD 3,013,606

OSCILLATING MECHANISMS Filed Nov. 14, 1958 5 Sheets-Sheet 2 Dec. 19,1961 GODDARD 3,013,606

OSCILLATING MECHANISMS Filed Nov. 14, 1958 5 Sheets-Sheet 3 "Lin i7 106Dec. 19, 1961 D. A. GODDARD 3,013,606

OSCILLATING MECHANISMS Filed Nov. 14, 1958 5 Sheets-Sheet 4 lIg lB I1gl-3l Lin \AMIIII 0110/11/ H103 QC/ I;

Dec. 19, 1961 D. A. GODDARD 3,013,606

OSCILLATING MECHANISMS Filed Nov. 14, 1958 5 SheetsShet 5 Due/2727 .5::::.U 6 0001420 3,0135% Patented Dec. 19, 1961 3,013,606 (BSQHLLATENGMEQHANEMS Denis A. Qoddard, Como, Quebec, Canada, assigns! to DominionEngineering Works Limited, Montreal, Quebee, Canada Filed Nov. 14, 1958,$01. No. 773,991 14 lClaims. (Cl. 162-355) This invention relates to amachine section supporting and oscillating mechanism which, whileparticularly adapted for supporting and oscillating the table rollsecion or sections of a Fourdrinier type paper-making machine, may beused in other relations where it is desirable or necessary to impartoscillating movement to one or more sections of a machine.

In the present instance the invention will be described as embodied in aFourdrinier paper machine, but, as indicated above, this is illustrativerather than limiting.

It is common practice in the paper making industry to provideoscillation at right angles to the direction of travel of a fourdririerwire, in the formation section of said wire, to assist in the paperformation" control and to endeavour to provide random distribution ofthe stock fibres across the face of the wire during the more liquid stae of the formation of the paper sheet.

The papermalrer has long desired to have a range of frequencies andamplitudes of oscillation at his disposal in order that he may vary theoscillation to meet varying conditions, such as, for example, a changein the stock condition and/or differences in the desired weight orstrength of the paper to be produced.

In the past the Fourdrinier type paper machines have been provided withthe oscillating section or sections sup ported on vertical, laminated,plate springs. Due to the non-adjustable nature of these laminated platesprings it is not feasible to utilize to any degree the frequencyamplitude range obtainable from an oscillation producing mechanismemployed for the oscillation of the section or sections of thpapermaking machine. The practical impossibility of setting up theconventional type of laminated spring support so that all laminates takean equal share of the load, together with corrosion, extreme stressreversals of the springs, continuous operation and a wide frequencyrange to which the springs cannot be matched, leads to early springfailure and frequent replacement of spring laminates. The replacementlaminates of incorrect length also aggravate the support structure andfrequently result in complete breakdown.

The pre ent invention proposes to overcome all of these disadvantagesand inacequate qualities, and to provide an oscillating mechanismcapable of a Wide range of fre quencies and amplitudes of oscillationadjustable to those of the oscillation producing mechanism. According toone embodiment of the present invention, the weight of the paper machineoscillating section or sections is taken on supporting members, strutsor pivot arms while adjustable spring-rate torsion bar springs, whichare adjustable as regards resonance wi h the forced frequencyoscillation of said oscillation producing mechanism, serve as energyreservoirs and thus assist in reducing the amount of power required formaintaining oscillation.

A prestressed torsion bar spring is anchored at one end to a stationaryportion of the Fourdrinier paper machine while the other end of thetorsion bar spring is secured to one end of a strut which in turn isrotatably connected at its other end to the oscillating section. In thepreferred arrangement, the said other end of a torsion bar spring iscarried in flexible bush bearings secured to the stationary portion ofthe paper machine for rotation of the lower end of the strut. The upperend of the strut is also rotatable about an axis carried in flexiblebush bearings secured to the oscillating section of the paper machine.The flexible elements of these hearings permit oscillation of the supporting struts without recourse to rolling or sliding bearings and theirattendant clearance, lubrication and other problems. Also, the dampingcharacteristics inherent in this flexible type bearing permit the use ofthe torsion bar springs at resonance or near resonance which otherwisewould not be desirable.

The torsion bar spring anchor may be rendered movable 'axialy of thetorsion bar spring, to alter the effective length of the torsion barspring, so that the spring rate or stiffness of the torsion bar springmay readily be adjusted for resonance with variations in the frequencyand amplitude of the forced oscillation for correct functioning. In anysingle oscillating section, torsion bar springs are arranged on eitherside of the machine and are prestressed in opposition.

The superior stability of an oscillating forming section mounted on thistype of prestressed pivotal support makes more practical the possibilityof dividing the section into parts which enable a papermaker to graduateor oppose oscillation in any number of separate sections. Due to t isstability the need for horizontal leaf springs normally employed in theconventional Fourdriniers as a means for estraining movement in thedirection of travel of the wire is eliminated.

The compact nature of this invention permits the independent mounting ofthe breast roll section and the table roll section if desirable. In thisconnection, according to another embodiment the weight of the breastroll is taken on pivotal members which comprise supporting brackets forthe breast roll which are adjustable as to the amount of prestressemployed but of fixed spring rate or stiffness of the torsion barspring. Due to the small mass involved in oscillating one roll, it isnot necessary to provide adjustable spring rate to torsion bar springsbut a different spring-rate torsion bar spring can be, in.- serted intothe mechanism if a different oscillation speed range is desired. Thespring-rate of the torsion bar spring in this embodiment is chosen asthe average for the speed range it is desired .to work in.

In this latter embodiment the prestressed torsion bar springs are eachanchored at one end to a stationary portion of the Fourdrinier papermachine while the other end of the torsion bar spring is connected tothe oscillating breast roll bearing brackets with the axis of thetorsion bar spring coinciding with the axis of the said bearings. As thetorsion bar spring of each breast roll bearing bracket is prestressed inopposition the stability of the mechanism during oscillation will beapparent.

From the foregoing it will .be. appreciated that a particular object ofthis invention is to provide a paper machine with pivotal supports forthe oscillating section or sections which are connected with prestressedtorsion bar springs which are adjustable as regards resonance with thefrequency of an oscillation producing mechanism in order to enable apapermaker to use a wider range of oscillation to meet a variation ofconditions which may be encountered during the course of manufacture.

Another object of this invention is to provide a pivotal supportingmeans for carrying the weight of the oscillating section or sections andtorsion bar springs connected to said pivotal supporting means formotion control of same during oscillation.

Still another object is to provide a means for resiliently supportingthe oscillating section of a paper machine which is capable ofincreasing the life of the mechanism used for producing oscillation, byreducing the force needed to maintain oscillation of said paper machinesection.

A further object is to provide flexible bearings for the pivotalsupporting structure which are capable of isolating the oscillatingsection or sections from vibrations not emanating from the oscillationproducing mechanism.

A still further object is to provide an oscillating section supportstructure of the character described with a simple and positive lockingmeans capable of maintaining said support structure in an uprightposition when required.

The above and other objects and characteristic features of thisinvention will be understood more readily from the following detaileddescription taken in connection with the accompanying drawings, inwhich:

FIG. 1 is a side elevational view of a Fourdrinier paper machineoscillating section in which one embodiment of this invention is shown.

FIG. 2 is a vertical sectional view taken along the lines 22 of FIG. 1.

FIG. 3 is a sectional view taken along the lines 33 of FIG. 1.

FIG. 4 is a plan view enlarged of a shake mechanism, showing itsconnection to the oscillating section of the paper machine of FIG. 1.

FIG. 5 is an enlarged elevational view, partly in section of theoscillating mechanism shown in FIGS. 1 and 2.

FIG. 6 is an end view of a bracket shown in FIG. 5.

FIG. 7 is an end view of another bracket shown in FIG. 5.

FIG. FIG. 5.

FIG. 9 is an end view of still another bracket shown in FIG. 5.

FIG. 10 is an end view, partly in section, showing the oscillatingmechanism at one side of the paper machine in a partial state ofassembly.

FIG. 11 is an end view similar to FIG. 10 but showing the oscillatingmechanism at the other side of the paper machine.

FIG. 12 is an enlarged elevational view of the torsion bar springanchoring means shown in FIGS. 1 and 3.

FIG. 13 is an end view of the anchoring means shown in FIG. 12.

FIG. 14 is a side elevational view showing a breast roll mounting of apaper machine according to another embodiment of this invention.

FIG. 15 is an enlarged elevational fragmentary view, partly in section,detailing the breast roll mounting shown in FIG. 14.

FIG. 16 is an end view of the breast roll mounting shown in FIGS. 14 and15.

FIG. 17 is a view of the opposite end of the breast roll mounting shownin FIG. 16.

FIG. 18 is an elevational view of the shake mechanism connection bracketshown in FIG. 16.

Referring more particularly to FIGS. 1 to 14, a pair of laterally spacedshake rails 5 and 6 are mounted adjacent one end on separate stands 7,each being provided with a flexible pedestal 8 which permits a smalldegree of lateral pivoting of the shake rails 5 and 6 relative to thestand 7. The shake rails 5 and 6 are held in spaced relation by girtrails 10 which are fitted in girt 8 is an end view of the support strutshown in rail brackets 11 on the underside of the shake rails 5 and 6.The girt rails are held at each end against displacement relative to thebracket 11 by a taper key 12. A plurality of table rolls 14 are mountedover the shake rails in end bearings 15 carried by the shake rails 5 and6.

The end of rails 5 and 6 remote from pivot stands 7 are downwardly andthen outwardly offset to provide two parallel extensions 16 for themounting of end bearing supports 17 for a breast roll 18 and themounting of stands 19 of a forming box 20 located intermediate thebreast roll 18 and the first table roll 14. The rear shake rail 6 isconnected to a shake mechanism, generally indicated at 22, through themedium of a linkage 23 pivotally connected to a bracket 24 mounted atone side of shake rail 6 as indicated at 25. The shake mechanism 22causes a lateral shaking movement of the shake rails 5 and 6 about theirpivotal mounting on stands 7 which in turn imparts a shaking movement tothe breast roll 18, forming box 20 table rolls 14 and the overlyingportion of a Fourdrinier wire 26. The underlying portion of wire 26 istrained around tensioning and guide rolls 27 and 28 on its return frompassage about a couch roll (not shown) which is located beyond the endof the shake rails remote from the breast roll.

The shake rails 5 and 6 are each connected remotely from their pivotalstands 7 to an oscillating mechanism generally indicated at 30 which ismounted on a stand 31. The oscillating mechanism 30 is connected to oneend of a torsion bar spring 32 having its other end secured in anadjustable anchor bracket 33 mounted on a stand 34.

As will be seen more particularly in FIGS. 5 to 11, each shake rail ofthe oscillating mechanism 30 is supported by a supporting member strutor pivot arm 35 provided with an upper bore 36, into which the outercasing of a flexible bush bearing 37 is press-fitted or keyed. A pivotpin 38 is then press-fitted or keyed into the inner casing of theflexible bush bearing 37. The ends of the pin 38 on either side of arm35 are fitted in split brackets 39 which are secured to the underside ofeach shake rail 5 and 6 so that the axis of pin 38 is in thelongitudinal direction of the corresponding shake rail. The pins 38 aresecured against rotation relative to their supporting brackets 39 bysuitable means which may consist of a key or, as shown, by press fittingthe two halves of the split brackets 39 about the pin by means ofclamping screws 40 (see FIG. 5). The ends of the arm 35 defining theupper bore 36 are recessed at 42 to receive an 0 seal ring 43.

The strut or pivot arm 35 is also provided with a lower bore 45 throughwhich a portion 46 adjacent one end of the torsion bar spring 32 isslidably fitted. The portion 46 of the torsion bar spring 32 and thebore 45 are provided with complementary keyways 47 and 48 (FIGS. 10 and11) to receive a key 49. Portions 50 on either side of torsion barspring portion 46 which are of slightly lesser diameter, are providedwith flexible bush bearings 51. The bearings 51 have their inner casingskeyed or press-fitted about the torsion bar spring portions 50. Theouter casings of bearings 51 are fitted into the split brackets 52 and52a which are secured to the stand 31 by bolts or other suitable meansso that the axis of torsion bar spring 32 parallels the axis of pin 38of the corresponding shake rail. The ends of the arm 35 defining thelower bore 45 are also recessed at 53 to receive an 0 seal ring 54.Screws 55 clamp the half-sections of brackets 52 and 52a about the bushbearings 51. The outer ends of the brackets 52 and 52a are fitted withcovers 59 and a seal ring 60.

As shown in FIGS. 12 and 13, the other end of torsion bar spring 32 issecured in an anchor bracket 33. The anchor bracket 33 is mounted on atable top 61 of stand 34 between guide rails 62 which permit the anchorbracket to be moved in the lengthwise direction of the torsion barspring 32 so that the said anchor bracket amass e 33 which is providedwith a bore 64 is adjustable along an end portion 65 of the torsion barspring 32 which is receivable in said bore. The bore 64 and the endportion 65 of torsion bar spring 32 are provided with complementarykeyways 66 and 67 into which a key 68 is fitted. Clamp bolts 69 throughguide rails 62 are loosened to permit sliding adjustment of the anchorbracket 33 and are tightened to secure the anchor bracket in itsadjusted position along the length of the torsion bar spring end portiones.

in H68. and ll end views of the struts or pivot arms 35 for the shakerails 5 and 6 respectively, are shown. In these views the upper andlower brackets 39 and 52a on the near side have been removed for thesake of clarity. By comparing FIGS. 10 or 11 with PEG. 13 it will beseen that the keyway 4'7 in the torsion bar spring portion 46 for theoscillating mechanism 30 is radially offset (FiGS. l0 and ll) withrespect to the keyway 67 in the opposite end portion 65 or" the torsionbar (FIG. 13) which is slidably fitted in the bore 64 of anchor 33. Whenthe end portion 65 or" one torsion bar spring is keyed to thecorresponding anchor 33 (see FIG. 13), the oitset position of keyway 47requires that the strut or pivot arm 35 of shake rail 5 be inwardlyinclined at about 5 from the perpendicular in order that the lowersleeve 45 may be keyed to the torsion bar spring portion as, as shown inFIG. 10. Similarly, when the end portion as of the other torsion barspring is keyed to the corresponding anchor 33 (see also FIG. 13), theoffset position of keyway 47 as shown in FIG. 11 requires that the strutor pivot arm 35 of shake rail 6 be inwardly inclined at about 5 inopposite direction to the strut or pivot arm shown in FIG. 10.

In order to move the struts or pivot arms 35 to a vertical positionsuitable levers (not shown) are inserted in transverse openings "1% inthe pivot arms 35. The

pivot arms 35 are then rotated outwardly about the axes of the torsionbar spring 32 and at the same time apply a torque to the torsion barspring 32 which tends to bias the pivot arms 35 to swing inwardly. Whenthe pivot arms 35 are in their vertical position (FIG. 5) a pin '72 isfitted in an opening ?3 provided in the end of pivot arm 35 adjacentbracket 52a. Bracket 52a is provided with a shoulder 74- against whichthe projecting portion of pin 72 bears to prevent rotation of the pivotarm 35 in response to the bias of the torsion bar spring 32. While FEGS.5 and 9 show the shoulder to be on one side of bracket 52a which issuitable for stepping rotation of the strut or pivot arm 35' of shakerail 5 in one direction, it will. be appreciated that the shoulder ofbracket 5% on pivot arm 35 of shake rail 6 will be on the reverse sidefor stopping rotation in the opposite direction.

When the stop pins 73; are in place the clamping screws 55 of the halfsections or" brackets 52 and 52a are tightened to bring the innersurfaces of the brackets to bear against the outer casing of thecorresponding flexible bush bearings 51 to prevent relative movementbetween the bracket and the said outer casing and therefore movement ofthe pivot arms 35 on either side of the vertical position is effectedthrough the flexible portion of the bush 51.

After the pivot arms are secured in their vertical position and theflexible bush bearings 51 are secured to the brackets 52, 52:: the shakerails 5 and 6 are secured by bolts or other suitable means to theflanges of the upper brackets 35' of the corresponding oscillatingmechanism 30. With the girt rails 1h emplaced in the brackets 11, theequal biasing or" the prestressed torsion bar spring in oppositedirections normally holds the struts or pivot arms 35 in verticalpositions and the stop pins '72 may be removed from the openings 73 asthese are only used to prevent unintended lateral movement of the shakerails. The size of that portion of each stop pin is reduced to a deg 'eewhich will normally hold the pivot arms in their upri ht position butwill be readily sheared oil under the action of the shake mechanismshould an operator neglect to remove the pins before actuating saidshake mechanism.

Each stand 31 is provided with an extension bracket 75 which supports adoctor stand 76 for a breast roll doctor 77.

In operation, the shake mechanism 22, sets up an oscillating movement tothe shake rails 5 and 6 at right angles to the direction of theFourdrinier wire. This oscillating movement is aided by the oscillatingmechanism 31; located substantially adjacent one end of the shake railswhich allows the rails to be moved back and forth about their pivotalmounting '8 located substantially adjacent the other end of the rails inresponse to the reciprocating motion of the shake mechanism 22. in thismanner the stock fibres receive a lateral dispersing motion during theirtravel along the wire from the breast roll which assists in formationcontrol and encourages random orientation of the fibres during theperiod that the stock water is draining.

The oscillating mechanism 3%} normally supports one end of the shakerails in an upright position. Due to the prestressing of the torsion barsprings 32 of each shake rail oscillating mechanism in oppositedirection, the forced-frequency oscillation imparted by the shakemechanism 22 can be suitably regulated to produce a stabilizedoscillation of the shake rails and related attached parts such as thebreast roll and the forming box.

As will be seen, when forced movement is imparted by the shake mechanism22 in one direction, the prestressing of one torsion bar spring is atleast partially diminished while the torque is increased in the opposingtorsion bar spring and thereby builds up a returning force in the secondmentioned torsion bar spring which will reduce the force required toinitially move the shake mechanism 22 at the beginning of its returnstroke.

During the oscillating movement of the oscillating mechanism iii theflexible bush bearings 37 and 51 are under shear from either side of thevertical position and have a damping eifect, permitting oscillation atresonant frequency with the spring mass and combination. This reducesany shock which might otherwise be imparted to the oscillating mechanismfrom the shake mechanism. These flexible bush bearings also absorbvibrations from other sources which might otherwise be imparted to theshake rails and interfere with the proper functioning of the shakemechanism.

In order that there will be complete harmony of resonance with thestroke of the shake mechanism, the torsion bar spring 32 is adjustableas to length to vary the frequency by moving the anchor 33longitudinally of the torsion bar spring between the guide rails 62. Thefrequence may also be varied by substituting a torsion bar spring of agreater or lesser cross-section. When the torsion bar springs are inresonance with the shake mechanism the amount of power required or theshake mechanism is greatly reduced, being only that necessary tomaintain motion. The length of the torsion bar spring may be varied, ifthe length and rate of shake mechanism is altered, to adjust the torsionbar springs to resonance with the new forced-frequency oscillation ofthe shake rails 5 and 6. The torsional prestress is applied to eachtorsion bar spring in opposite directions suffciently to ensure thatmovement of the oscillating mecl2- anism, does not completely unwindeither torsion bar spring or set up stress reversals in either torsionbar spring and thereby cause fatigue failure in the torsion bar springs.This is accomplished by applying a sufficient prestress to each torsionbar spring so that the complete unwinding of one torsion bar springrequires a greater movement in one direction than the distance affordedby the maximum stroke of the shake mechanism.

Although FIG. 1 of the drawings shows only a single pair of oscillatingmechanisms with torsion bar springs. The invention also contemplates theuse of several similar oscillating mechanisms located at differentstations along the length of a paper machine in the forming sectionthereof.

The invention also contemplates the separate mounting of a breast rollfor independent oscillation by a shake mechanism of the breast roll. Inthis manner the breast roll and the shake rails with the table rollsthereon may be oscillated at different frequencies.

FIGS. 14 to 18 show a modification in which the breast roll 30 of aFourdrinier paper machine is separately mounted on laterally spacedstands 81 relative to the shake rails 82 and table rolls 83. The breastroll 80 is mounted between laterally spaced bearing brackets 84- each ofwhich comprises upper and lower sections 84:: and 84b hinged at 85 topermit insertion of a spherical breast roll bearing 86 therebetween, andare secured by a clamping bolt 87 when fitted about said breast rollbearing. Each breast roll bearing bracket 04 has a longitudinal bore 88through the base through which a supporting tube 89 is slidably fitted.The ends of the tube 39 adjacent the outer ends of the breast rollbearing bracket bore 88 are reduced, as indicated at 90, to provideshoulders 91 against which the inner ends of flexible bush bearings 92are abutted when fitted about the reduced portions 90. The flexible bushbearings are fitted in split bearing support brackets 93 and 93a. Thesplit brackets 93 and 9311 are clamped against the outer casing of bushbearing 92 by clamping screws 93x. Said brackets 93 and 93a are suitablysecured to the table of stand 31. The right hand end of the reducedportion 90 of tube 89 is further reduced as indicated at 94 to provide ashoulder 95. Tube portion 94 is threaded adjacent the shoulder 95 toreceive a clamping nut 96 which bears against the shoulder 95 and theadjacent end of the inner casing of bush bearing 92 to prevent movementof the casing relative to the tube.

A torsion bar spring 100 having thickened ends 10 1 and 102 is fittedthrough the tube 89 with its end 101 secured against rotation relativeto the tube by means of a securing pin 103 which extends through alignedpin openings in the tube end portion 94 and said torsion bar spring end101. The tube 89 is then secured to the base of the breast roll bearingbracket section 84b by pins 104 to prevent rotation of the tube 89 inthe bore 88 of bracket section 84b. The reduced portion of the torsionbar spring 100 passes freely through the tube 39 and the bearing supportbracket 93 and its thickened end 102 is mounted in a split anchoringbracket 105 having its base suitably secured to the table of stand 81.The thickened portion 102 of torsion bar spring 100 has a marginalextension 106 which projects beyond the outer end of anchoring bracket105. A lever 107 has one end fitted about extension 106 and securedthereto by a retaining pin 108. The other end of lever 107 is providedwith a threaded opening through which a bolt 109 is adjustably threadedso that the lower end thereof is engageable with the base 110 ofanchoring bracket 105.

In assembling the breast roll bearing brackets 84 they are arrangedbetween the support bearings 93 and 93a with a slight inward incline,preferably about from the vertical position. After the pins 103 and 108have been secured through the opposite thickened ends of the torsion barspring to secure said ends to portion 94 of tube 89 and to lever 107respectively against relative rotation therebetween, the bolt 109 isadjusted vertically to engage the base 110 of bracket 105 so as toprevent further downward movement of the lever 107. The breast rollhearing brackets 84 are then rotated about their longitudinal axesextending through the bore 88 to a vertical position. As one end of thetorsion bar spring is spring anchored to the lever 107 which is heldagainst rotation by bolt 109, and as the other end of the torsion barspring is secured to the end portion 94 of tube 89 the outward rotationof the brackets 84 applies a torsional prestress to the torsion bar.When the thus prestressed pivotal mechanisms of the breast roll brackets84 are in their vertical positions pins 112 are inserted in end openingsof the bracket sections 84b and are adapted to bear against stops 114carried by the supporting brackets 93a. The pins .112 are of a materialand thickness which is adequate to hold the breast roll bearing brackets84 in their vertical positions against the normal bias of the torsionbar spring, but which will rupture if additional external force beapplied, such as by the shake mechanism attached thereto, and theoperator has neglected to remove the pins before actuating the shakemechanism. Holes 115 may also be provided in the transverse direction ofthe brackets 84 so that a lever (not shown) may be inserted therethroughto enable rotation of the brackets 84 about their longitudinal axes.

When the brackets 84 are secured in their vertical positions the uppersections 8411 are swung about their pivots to a position which enablesthe mounting of the spherical bearings 36 on the journals of the breastroll 80. The sections 34a are then clamped about bearings 86 by bolt 87.The right hand breast roll bearing bracket 84. as shown in FIG. 16 isprovided with an extension 116 on the outer side thereof upon whichshake mechanism attaching bracket 117 is mounted and secured in place bya key 118 and bolts 119. The upper end of bracket 117 is pivotallyconnected at 120 to links 121 arranged on either side of said brackets.The links 121 form a part of a shake mechanism similar to that shown inFIG. 4.

In operation, a shake mechanism of the type shown in FIG. 4, which islinked to the shake mechanism attaching bracket 117 carried by one ofthe breast roll bearing brackets 84, oscillates the breast roll bearingbrackets about their longitudinal pivotal axes extending through thebores 88 of the base portions of said brackets against the opposedbiasing of the torsion bar springs in the same manner as described inconnection with the pivoting of the strut 35 of the above oscillatingmechanisms 30 against the biasing of their torsion bar springs 32. Theflexible bush bearings 92 have the same dampening and cushioning efiectbetween the tube 39 and the support brackets 93 and 93a as thatpreviously described in relation to the bearings 51, brackets 52 and 52aand the torsion bar spring end portions 50.

Here, the prestressing of the torsion bar spring 100 is adjustable. Thisprestressing adjustment is effected by vertical movement of the bolt 109in the free end of lever 107 so that there will be an equal stress oneach torsion bar spring 100 in opposite directions. Prestressing of thetorsion bar spring 100 in opposite directions should be sufiicient toensure that the unwinding torsion bar spring 100 will not reach a pointof zero or reverse stress at the maximum stroke of the shake mechanismin order that the torsion bar spring will not be subjected to reversestresses, and fatigue failure. In this particular embodiment the loadingfor one roll is so light that an adjustable spring rate torsion barspring has not been provided, the size being chosen to suit the averageoscillation rate. Large changes in speed may be accommodated by fittinga different length torsion bar spring.

What I claim is:

1. In an oscillating mechanism, a pair of laterally spaced supportingmembers pivotally mounted at their lower ends to rotate about separateparallel axes, said supporting members each having an upper portionconnected to opposite sides of a member to be oscillated to pivot aboutaxes parallel with the pivotal axes of the lower ends of said supportingmembers, and means normally applying a turning moment to each of saidsupporting members tending to simultaneously force pivotal movement ofsaid supporting members about their lower axes in opposed directions sothat oscillating movement of said mechanism in one directionprogressively diminishes the turning moment in one of said supportingmembers and progressively increases the turning moment in the other ofsaid supporting members, characterized in that the maximum increasedturning moment of said last mentioned supporting member is utilized asan impelling force during the initial oscillating movement in theopposite direction.

2. In an oscillating mechanism, a pair of laterally spaced supportingmembers, each pivotally connected at its lower end to a fixed base sothat the supporting memhere can turn about separate parallel axes, amember to be oscillated supported by said supporting members, saidmember to be oscillated being connected to said supporting memberstopivot about axes spaced from and parallel with the pivotal axes at thelower ends of said supporting members, and a torsion bar spring axiallyaligned with the lower pivotal axis of each supporting member, eachtorsion bar spring having one end secured to a corresponding supportingmember and means for anchoring a portion of said torsion bar springremote from its point of securing to said supporting member to resistrotary move ment of the anchored portion of said torsion bar spring,said torsion bar springs being prestressed to apply a force tending topivot each of said supporting members about its lower axis in opposeddirections so that oscillating movement in any one direction reduces thepivoting force of one torsion bar spring and increases the pivotingforce of the other torsion bar spring characterized in that the saidincreased force is utilized an initial impelling force to thecorresponding supporting member during its initial oscillating movementin the opposite direction.

3. An oscillating mechanism as set forth in claim 2, in which theopposed prestressing of said torsion bar springs applies forces urgingsaid supporting members to pivot toward each other.

4. An oscillating mechanism as set forth in claim 2, in which thetorsion bar springs are prestressed for an amount sntiicient to ensurethat they will not be subjected to reverse stresses during saidoscillating movement.

5. An oscillating mechanism as set forth in claim 2, in which saidanchoring means is movable along the length of the torsion bar spring toalter the eifective length of the bar so that the spring rate orstiffness of the torsion bar spring may be adjusted for resonance withvariations in the frequency and amplitudes of oscillation.

6. In a Fourdrinier paper machine a table roll section including a pairof laterally spaced shake rails sup porting a plurality of table rollsupon which a paper forming wire moves in the longitudinal direction ofthe shake rails, and oscillating means supporting said shake rails, saidoscillating means comprising a pair of laterally spaced supportingmembcrs, each pivotally connected at its lower end to a fixed base sothat the supporting member can turn about a separate parallel axis, eachsupporting member being also pivotally connected at its upper end to oneof said shake rails for vertical support of said rail and to rotateabout a separate axis spaced from and parallel to the said axis at thelower end of said supporting member, and a pair of torsion bar springs,each torsion bar spring having one end secured to a correspondingsupporting member in axial alignment with the lower pivotal axis of saidsupporting member and anchoring means securing a portion of said torsionbar spring located remotely from the end of said torsion bar sprinsecured to said supporting member to resist turning movement theanchored portion of said torsion bar spring, said torsion bar springsbeing prestressed intermediate the anchored portion and the end securedto the supporting member to apply a force tending to pivot saidsupporting members about their lower axes in opposed directions so thatapplication of oscillating movement in any one direction reduces thepivoting force of one torsion bar spring and increases the pivotingforce of the other torsion bar spring characterized in that the saidincreased pivoting force is utilized as an initial impelling force tothe corresponding sup- '19 porting member during its initial oscillatingmovement in the opposite direction.

7. A Fourdrinier paper machine as set forth in claim 6, including ashake mechanism connected to one of said shake rails to produceoscillation substantially at'ri'ght angles to the line of travel of saidwire.

8. A Fourdrinier paper machine as set forth in claim 6, including abreast roll mounted on said shake rails adjacent one end thereof to beoscillated therewith.

9. A Fourdrinier paper machine as set'forth in claim 6, in which saidoscillating means supports said shake rails adjacent one end thereof andincludes means separately supporting said shake rails adjacent theiropposite ends for pivotal movement about vertical axes.

10. A Fourdinier paper machine as set forth in claim 6, in which saidanchoring means comprises an anchor bracket provided with a bore inwhich a portion of the torsion bar spring is slidably fitted, meansengageable between the torsion bar spring and the anchor bracket toprevent rotation of the bar relative to the bracket, and a fixed standprovided with guide rails for sliding support of said anchor bracket topermit adjustment of said anchor bracket along the length of saidtorsion bar spring to alter the efiective length of the torsion barspring so that the spring rate or stiffness of said torsion bar springmay be adjusted for resonance with variations in the frequency andamplitudes of oscillation.

11. A Fourdrinier paper machine as set forth in claim 6. in which thelower end of said supporting member is provided with a bore and ispositioned between a pair of brackets secured to a fixed base and inwhich said torsion bar spring extends through bores in said bracketsaxially aligned with the bore in the lower end of said supportingmember, means securing said torsion bar spring in the bore of saidsupporting member to prevent relative rotary movement between saidtorsion bar spring and said supporting member and flexible bush bearingsmounted in the bores of said brackets, said bearings having their innercasings secured about the torsion bar spring and their outer casingssecured to the surface of the bracket bores whereby oscillation of saidsupporting member is cushioned by the flexible portion between the innerand outer casings of said flexible bush bearings.

12. A Fourdrinier paper machine as set forth in claim 6, in which theupper end of one of said brackets is provided with a stop member, and apin receivable in an end opening in said supporting member andengageable with said stop member to retain said supporting member in anupright position against the biasing force of the torsion bar springwhen the mechanism is not oscillating.

13. A Fourdrinier paper machine as set forth in claim 6, in which theupper end of each supporting member is provided with a bore and ispositioned between a pair of brackets secured to the under side of acorresponding shake rail, said brackets being provided with boresaxially aligned with the bore in the upper end of the supporting member,a pin extending through the bores in said brackets and in saidsupporting member and having its axis in spaced parallel relation to thelower pivotal axis of said supporting member, means securing said pin tosaid brackets to resist relative rotation therebetween and a flexiblebush bearing having its inner casing fitted about an intermediateportion of said pin to resist relative rotation between the said innercasing and the pin and having its outer casing secured in the bore ineach end of said breast roll to support said breast roll by its bearingsfor rotary and pivotal movement relative to said breast roll brackets,said breast roll brackets having their lower ends mounted on fixedstands to pivot about spaced, horizontal axes, and a torsion bar springaxially aligned with the lower pivotal axis of each breast rollsupporting bracket and having one end secured to said breast rollbracket and the other end secured to an anchoring means mounted on saidfixed stand, the intermediate portion of said torsion bar springs beingprestressed in opposition to apply forces urging said breast rollsupporting brackets to pivot towards each other, characterized in thatoscillation of said breast roll in any one direction reduces thepivoting force of one torsion bar spring and increases the pivotingforce of the 12 other torsion bar spring whereby the increased pivotingforce is utilized as an initial impelling force to the correspondingbreast roll supporting bracket during its initial stage of oscillatingmovement in the opposite direc tron.

References Cited in the filo of this patent UNITED STATES PATENTS Re.17,381 Aldrich July 30, 1929 1,629,087 Aldrich May 17, 1927 1,917,287Aldrich et al. July 11, 1933 2,821,292 Spurlin Jan. 28, 1958 FOREIGNPATENTS 681,896 Germany Oct. 4, 1939

